This invention relates to the display and prediction of tides and in particular to a device that continuously indicates the existing level of tide; whether it is rising or falling; and the prediction of future tides for any day in the future, using electronic means and visually graphic displays.
Tide states are of interest to boaters, sailors, fishermen surfers, shellers and coastal residents since the tides influence their activities. While there are over 40 celestial bodies that affect the tides, the moon has the dominant influence by a factor of approximately three times any other body. Tides are produced as a result of the moon's gravitational forces on Earth's waters, and occur approximately twice per calendar day, since the gravitational effect occurs on both sides of the Earth, diametrically opposed. The lunar cycle is 24 hours; 50 minutes; 28.33 seconds. The tide has two highs and two lows during each cycle. The other celestial effects can change the tides by over one hour, but over a period of time it averages out to the lunar cycle. Therefore each high tide occurs 12 hours; 25 minutes; 14.16 seconds after the previous high tide; and likewise for the low tides, when considered over any period of time.
If a conventional watch time hand rotates 360 degrees in 12:00:00 hours a tide indicator would rotate faster by the factors given above. The ratio of real time to lunar (tide) time is accordingly 1.03505. It is this fixed and unvarying ratio that is used in this invention to predict and calculate tide conditions.